The Champions League brings out some of the greatest features of football, including some incredible comebacks.

What are the most incredible comebacks the Champions League has ever seen?

Manchester United vs. Bayern Munich, 1999 final

Manchester United were down by a goal heading into stoppage time of the 1999 Champions League final. Their quest for the first treble in English history was going to fall short. They scored 2 goals in regulation time to win the cup.

Liverpool 3 AC Milan 3. Liverpool wins on penalties 3-2 (2005)

It is referred to as the "Miracle of Istanbul" by Liverpool fans and certainly was one of the most amazing comebacks in the Champions League and world football history.

Milan had jumped out to a 3-0 halftime lead. But Liverpool mounted a comeback right out of the break, scoring three times by the 60th minute to bring things level. With neither team able to break the 3-3 deadlock, the result was settled on penalties.

Barca overturns 4-0 deficit

First leg result: PSG 4-0 Barcelona

Second leg result: Barcelona 6-1 PSG (2016/17)

In 2016/17, Barcelona became the first team to fight back from four goals down to win a UEFA Champions League tie – only the fourth time it's been done in any UEFA club competition tie. The craft of Messi and the exuberance of Neymar were too much for PSG to contain in the return leg.

As Roma vs Barcelona

First leg result: Barcelona 4–1 Roma

Second leg result: Roma 3–0 Barcelona; Roma advance on away goals

Barcelona entered the second leg of their quarterfinal clash with Roma in a comfortable position. The Catalans had not lost a match in domestic or Champions League play all season and had not tasted defeat in 18 straight matches including a 4–1 thrashing of Roma in the first leg of the competition at Camp Nou. However, Roma pulled a surprise at the Stadio Omypico and they advanced ahead of Barca on away goal rules.

AC Milan were the reigning champions and thrashed Deportivo, 4-1, in the first leg at the San Siro. It was a demolition and Milan could have easily won by more. Astonishingly, Deportivo La Coruna three first-half goals and Fran González's second-half strike gate crashed Milan hopes of retaining the Champions League crown.

Spanish giants Real Madrid were stunned at the Principality stadium by Monaco.

Chelsea vs Napoli

Napoli 3-1 ChelseaChelsea 4-1 Napoli (aet) (2011/12)

Losing 3-1 at Napoli in the first leg looked like the start of a Champions League elimination that would have fit in a season to forget, but with the able leadership of John Terry, Chelsea put in a masterful performance at Stamford Bridge and advance over Napoli.